<?php

/**
 * 容器
 */
class Container implements ArrayAccess
{
    private $values = [];
    private $factories;
    private $protected;
    private $frozen = [];
    private $raw = [];
    private $keys = [];

    /**
     * Instantiate the container.
     *
     * Objects and parameters can be passed as argument to the constructor.
     *
     * @param array $values The parameters or objects.
     */
    public function __construct(array $values = array())
    {
        $this->factories = new SplObjectStorage();
        $this->protected = new SplObjectStorage();
        foreach ($values as $key => $value) {
            $this->offsetSet($key, $value);
        }
    }

    /**
     * Sets a parameter or an object.
     *
     * Objects must be defined as Closures.
     *
     * Allowing any PHP callable leads to difficult to debug problems
     * as function names (strings) are callable (creating a function with
     * the same name as an existing parameter would break your container).
     *
     * @param string $id The unique identifier for the parameter or object
     * @param mixed $value The value of the parameter or a closure to define an object
     *
     * @throws RuntimeException Prevent override of a frozen service
     */
    public function offsetSet($id, $value)
    {
        if (isset($this->frozen[$id])) {
            throw new RuntimeException(sprintf('Cannot override frozen service "%s".', $id));
        }
        $this->values[$id] = $value;
        $this->keys[$id] = true;
    }

    public function set($id, $value)
    {
        $this->offsetSet($id, $value);
    }

    /**
     * Gets a parameter or an object.
     *
     * @param string $id The unique identifier for the parameter or object
     *
     * @return mixed The value of the parameter or an object
     *
     * @throws InvalidArgumentException if the identifier is not defined
     */
    public function offsetGet($id)
    {
        if (!isset($this->keys[$id])) {
            throw new InvalidArgumentException(sprintf('Identifier "%s" is not defined.', $id));
        }
        if (
            isset($this->raw[$id])
            || !is_object($this->values[$id])
            || isset($this->protected[$this->values[$id]])
            || !method_exists($this->values[$id], '__invoke')
        ) {
            return $this->values[$id];
        }
        if (isset($this->factories[$this->values[$id]])) {
            return $this->values[$id]($this);
        }
        $raw = $this->values[$id];
        $val = $this->values[$id] = $raw($this);
        $this->raw[$id] = $raw;
        $this->frozen[$id] = true;
        return $val;
    }

    public function get($id)
    {
        return $this->offsetGet($id);
    }

    /**
     * Checks if a parameter or an object is set.
     *
     * @param string $id The unique identifier for the parameter or object
     *
     * @return bool
     */
    public function offsetExists($id)
    {
        return isset($this->keys[$id]);
    }

    public function exists($id)
    {
        return $this->offsetExists($id);
    }

    /**
     * Unsets a parameter or an object.
     *
     * @param string $id The unique identifier for the parameter or object
     */
    public function offsetUnset($id)
    {
        if (isset($this->keys[$id])) {
            if (is_object($this->values[$id])) {
                unset($this->factories[$this->values[$id]], $this->protected[$this->values[$id]]);
            }
            unset($this->values[$id], $this->frozen[$id], $this->raw[$id], $this->keys[$id]);
        }
    }

    /**
     * Marks a callable as being a factory service.
     *
     * @param callable $callable A service definition to be used as a factory
     *
     * @return callable The passed callable
     *
     * @throws InvalidArgumentException Service definition has to be a closure of an invokable object
     */
    public function factory($callable)
    {
        if (!method_exists($callable, '__invoke')) {
            throw new InvalidArgumentException('Service definition is not a Closure or invokable object.');
        }
        $this->factories->attach($callable);
        return $callable;
    }

    /**
     * Protects a callable from being interpreted as a service.
     *
     * This is useful when you want to store a callable as a parameter.
     *
     * @param callable $callable A callable to protect from being evaluated
     *
     * @return callable The passed callable
     *
     * @throws InvalidArgumentException Service definition has to be a closure of an invokable object
     */
    public function protect($callable)
    {
        if (!method_exists($callable, '__invoke')) {
            throw new InvalidArgumentException('Callable is not a Closure or invokable object.');
        }
        $this->protected->attach($callable);
        return $callable;
    }

    /**
     * Gets a parameter or the closure defining an object.
     *
     * @param string $id The unique identifier for the parameter or object
     *
     * @return mixed The value of the parameter or the closure defining an object
     *
     * @throws InvalidArgumentException if the identifier is not defined
     */
    public function raw($id)
    {
        if (!isset($this->keys[$id])) {
            throw new InvalidArgumentException(sprintf('Identifier "%s" is not defined.', $id));
        }
        if (isset($this->raw[$id])) {
            return $this->raw[$id];
        }
        return $this->values[$id];
    }

    /**
     * Extends an object definition.
     *
     * Useful when you want to extend an existing object definition,
     * without necessarily loading that object.
     *
     * @param string $id The unique identifier for the object
     * @param callable $callable A service definition to extend the original
     *
     * @return callable The wrapped callable
     *
     * @throws InvalidArgumentException if the identifier is not defined or not a service definition
     */
    public function extend($id, $callable)
    {
        if (!isset($this->keys[$id])) {
            throw new InvalidArgumentException(sprintf('Identifier "%s" is not defined.', $id));
        }
        if (!is_object($this->values[$id]) || !method_exists($this->values[$id], '__invoke')) {
            throw new InvalidArgumentException(sprintf('Identifier "%s" does not contain an object definition.', $id));
        }
        if (!is_object($callable) || !method_exists($callable, '__invoke')) {
            throw new InvalidArgumentException('Extension service definition is not a Closure or invokable object.');
        }
        $factory = $this->values[$id];
        $extended = function ($c) use ($callable, $factory) {
            return $callable($factory($c), $c);
        };
        if (isset($this->factories[$factory])) {
            $this->factories->detach($factory);
            $this->factories->attach($extended);
        }
        return $this[$id] = $extended;
    }

    /**
     * Returns all defined value names.
     *
     * @return array An array of value names
     */
    public function keys()
    {
        return array_keys($this->values);
    }

    public function __get($name)
    {
        if ($this->offsetExists($name)) {
            return $this->offsetGet($name);
        }
        throw new InvalidArgumentException(sprintf('Identifier "%s" is not defined.', $name));
    }

    public function __call($name, $arguments)
    {
        if ($this->offsetExists($name)) {
            return call_user_func_array($this->offsetGet($name), $arguments);
        }
        throw new InvalidArgumentException(sprintf('Identifier "%s" is not defined.', $name));
    }
}